Development of quad thermistor for wind direction measurement

We are trying to improve the reproducibility of computational fluid dynamics analysis (CFD) of characteristics of exhaust from gas water heaters, and detailed exhaust anemometry is necessary to do so. However, the split-film probes used in existing anemometers are expensive and difficult to handle. Previous studies have suggested the possibility of using two thermal anemometers and a shield to measure wind direction using a device that simulates a tandem anemometer. In this study, we developed a measurement device called a "quad thermistor" that uses four thermal anemometers and a shield to measure wind direction with higher accuracy. The quad thermistor was evaluated in experiments in an Eiffel-type wind tunnel and two methods were used to calculate the wind direction. The results were validated by comparison with results from a CFD analysis, which roughly reproduced past measurements. One of the two calculation methods could determine the wind direction in some detail.